Owners and operators of personal computers regularly must face the fact that changes in computer technology move beyond the technology embodied in a particular machine in which they have invested. As computer manufacturers advance to new generations of equipment, they often change to a new bus architecture. An example is the adoption of Micro Channel Architecture (MCA) by International Business Machines Corporation (IBM) for use in IBM PS/2 personal computers, to replace the widely popular Personal Computer Architecture (PCA) previously used in IBM PC, PC XT, and PC AT computers. Peripheral device interface circuits embodied in adapter cards provided with edge contacts compatible with the PCA system cannot be used with the MCA system, and conversely.
Thus, a user who is considering upgrading to a new generation of computer technology which employs a different bus architecture must replace not only the central processing unit, but all of the peripheral device interface adapters purchased for use in connection with the earlier machine. This may include terminal emulators for communicating with mainframe computers, modems, memory expansion cards, graphics adapters, printer interfaces, and the like. If, for example, a corporation decides to provide terminal emulation capability for a large group of personal computers to enable them to communicate with the corporation's mainframe computer, the purchase of an adapter board for each of the personal computers is usually required. However, if the corporation also is considering upgrading the personal computers to machines with a different, perhaps more advanced, bus architecture, it faces a dilemma. If the needed capability is immediately purchased, it may have to be purchased again in the form of new adapter boards compatible with the new bus architecture. If the corporation postpones upgrading to the new bus architecture, it will be sacrificing the needed terminal emulation capability during the interim period.
Another aspect of the difficulties faced by personal computer users and owners is the current competition between the MCA personal computer bus and the Extended Industry Standard Architecture (EISA) personal computer bus. Certain manufacturers of "clones" of the popular IBM PCA bus architecture have recently embarked upon a course of action to promote the 32-bit EISA bus as an alternative to the MCA bus. The EISA bus is being promoted at least partly to postpone the obsoletion of older 8-bit PC bus adapter cards and 16-bit PC/AT adapter cards, as well as to provide an upgrade path to a 32-bit architecture which is compatible with at least some existing interface adapters. Many computer installations will inevitably wind up with a mix of MCA machines, PCA machines, EISA machines, and perhaps even other personal computer architectures such as the NuBus architecture. The proliferation of bus architectures has created a need for interface adapter boards for personal computers which increases flexibility in moving the boards from computer to computer for upgrades, enhancements, replacement, and the like.
A related problem faced by owners is computer inventory or asset maintenance and control. The need to provide a different peripheral adapter for each different type of personal computer utilized, even though the basic functions of the peripheral adapters may be the same, makes the tasks of selecting, acquiring, storing, maintaining, and repairing a large number of different peripheral adapters unnecessarily complicated. It would be more efficient if a single function peripheral adapter were operative in more than one computer bus architecture.
Accordingly, there is a need in the computer industry for an adapter board that is compatible with and can be plugged into more than one type of computer bus architecture.